Schematic of the pressure generator. All high pressure components were supplied by HiP. Junctions, valves, and connecting nipples were rated to . The pump was rated for use at . The rupture disk is included to prevent accidental over pressurization.
The outside diameter sapphire tubes were ground at the ends, as shown, to ensure roundness. The tubes protrude slightly past the ends of the ferrules; in this way the ferrules are fully supported and do not deform under load.
Schematic of the sample fixture: (1) Stainless steel capillary tube from the pressure generator, (2) stainless steel ferrules, (3) high pressure adaptor, (4) high pressure elbow coupling, (5) high pressure adaptor, (6) pipe to “Swagelok” fittings, (7) polyimide ferrules, (8) stainless steel end cap, (9) aluminum end support block, (10) high temperature epoxy resin filler, (11) fixing cap screws, (12) base plate, (13) fixing cap screws, and (14) aluminum block supporting the high pressure elbow. T-nuts on parts 11 running in a slot machined in the underside of the base plate (part 12) allowed the end support block (part 9) to be slid backwards and forwards enabling quick assembly of the sample fixture.
(a) The sample fixture ready to use with a sapphire tube and heater block in place, but with the sheet metal guard removed. (b) The complete sample fixture with the sheet metal guard in place.
The heating block assembly consisted of two similar aluminum pieces as shown (top). They were clamped around the sapphire tube as shown (bottom). The screws were lightly spring loaded to allow for differential thermal expansion, while ensuring adequate thermal contact between the heating blocks and tube.
X-ray transmission calculated using the total thicknesses of sapphire (solid line) and steel (dotted line) in the beam paths during the reported test experiments.
Data from a time resolved hydration study of class H cement at and using exposures. The quality is sufficient to identify and quantify, as a function of time, most of the crystalline phases involved in the hydration process.
Comparison of diffraction data recorded using sapphire (solid line) and steel (dotted line) tubes at 40 and , respectively. Exposure times were in both cases. The intensity scale is arbitrary and the two data sets have been scaled for comparison.
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